In the past it has not been possible to form translucent antiperspirant stick compositions because of the physical and chemical characteristics of the antiperspirant active. Translucent gel bases, known in the art, are produced using a metal stearate (most commonly sodium stearate) as the gellant. The presence of an acid, such as an antiperspirant active, in the gel base interferes with the metal stearate and converts it to stearic acid which causes the stick to break down, become extremely soft or inhibit gellation.
Antiperspirant sticks known in the art are produced using waxy gellants such as stearyl alcohol, cetyl alcohol and hydrogenated caster oil. The acidity of the antiperspirant active does not interfere with or break-down these gellants, however, the sticks are mostly white.
It is known in the art to produce transparent deodorant compositions since most deodorant actives do not interfere with the integrity of the gel base. For example, Canadian Patent 1196867 to Geria teaches a non aqueous transparent deodorant stick comprised of sodium stearate, propylene glycol, antimicrobial agents (deodorant actives) and ethanol. These sticks are shown to be stable and non-staining. Antiperspirant actives are not taught as a suitable additive.
EP Patent 107330 to Leubbe et al. teaches a clear cosmetic gel stick which can be used to deliver deodorants or other cosmetic materials. Delivery of antiperspirant actives is not taught. The clear gel sticks are comprised of an aliphatic, polyhydric alcohol, a soap, a hydro-alcoholic soluble emollient of the formula R(OC.sub.3 H.sub.6).sub.a (OC.sub.2 H.sub.4).sub.b OH, and water.
U.S. Pat. No. 4,440,742 to Marschner teaches deodorant stick compositions which comprise an alkali metal bi-carbonate as a deodorizing agent dissolved in a polyalcohol optionally mixed with a monoalcohol, solidified by an alkali metal salt of a saturated fatty acid gelling agent. Additional ingredients such as perfumes, colouring agents, ultraviolet absorbers can be added to enhance the color or improve the aesthetic value. The sticks may be transparent or opaque depending upon the amount of bicarbonate added and the particular ingredients employed. Antiperspirant stick compositions are not taught nor is antiperspirant active shown to be a suitable additive.
EP Patent 0291334 to Burger et al. teaches antiperspirant compositions in the form of a transparent stick. The antiperspirant compositions are comprised of an aluminum salt, a nonionic surfactant, a liquid oil which is immiscible with water. The transparent sticks are produced by combining an oil phase (liquid oil) and an aqueous phase (water, aluminum salt, and nonionic surfactant) where the components and quantities of the components are such the two phases have approximately the same refractive index. The nonionic surfactant includes the gellation.
U.S. Pat. No. 4,743,444 to McCall teaches deodorant or antiperspirant sticks. The sticks are comprised of a liquid base, benzylidene sorbitol, the astringent salt or deodorant active, fatty alcohol and optionally volatile silcone oil. The liquid base is selected from nonohydric alcohols, polyhydric alcohols, water or mixtures thereof. The deodorant or antiperspirant sticks are claimed as being transparent however, there is nothing in the patent which exemplifies this claim.
Translucent antiperspirant sticks known in the art have not been commercially viable because they are not aesthetically pleasing to the consumer. This invention overcomes that problem by producing an antiperspirant stick that contains antiperspirant actives and that are aesthetically pleasing to the consumer.
It is an object of this invention to show antiperspirant stick compositions that are translucent.
It is further an object of this invention to show antiperspirant compositions that are translucent and do not leave a visible white residue on the skin.
It is further an object of this invention to show translucent antiperspirant stick compositions wherein the stability of the stick is improved by the use of a silicone carboxy acid.